To get started with Android/BoulzorROM, you'll need to get familiar with Git and Repo.
To initialize your local repository using the BoulzorROM trees, use a command like this:
repo init -u git://github.com/BoulzorROM/android.git -b lineage-15.0
Then to sync up:
repo sync -c -f -j16 --force-sync --no-clone-bundle --no-tags